Bull and Schelling drew strength from a shared realisation that informal collaboration between the great powers, or the nuclear-armed superpowers, was possible in the absence of an overarching sovereign. An international version of Hobbes’ leviathan was not necessary. This collaboration was possible because the great powers were interrelated by common interest as well as competitive interest: they could limit the latter (according to Bull if they so chose as responsible heirs of the European international society and according to Schelling if they appreciated the nuclear predicament which made cooperation a requirement for survival).

But there is also a sense in both scholars’ writings that the common interest can be extended much further towards situations of purer cooperation where the competitive element in international politics is almost obscured. In Schelling’s work, this approach is evident in The Strategy of Conflict where he draws on theories of pure coordination where social units need to maximise their collaboration to emerge with a common focus or pattern.^[72] This encourages a potentially hazardous optimism. For example, Schelling regarded the limits being observed by US action in Vietnam in the mid-1960s as an important case of strategic bargaining, where those limits were being clearly communicated to North Vietnam.^[73] But the likelihood of success relied on Schelling’s universalistic assumption that Hanoi was motivated by common as well as competitive interests. North Vietnam’s political interests turned out to be much more zero-sum than he perhaps realised, and the moderating impact of nuclear weapons upon state ambitions did not extend as far as he had thought.

Schelling has been criticised for an approach which encourages the exploitation of violence in international affairs and risks making the world a more dangerous and violent place.^[74] But here he emerges as rather too optimistic about the possibilities of strategic cooperation and the limitation of violence, and possibly exaggerates the extent of common interest between strategic actors. Yet it is this sort of logic which helps explain the award of the Nobel Prize, and the appeal of his work beyond strategic studies into sociology and theories of international regimes.

Bull’s contemporaneous work from the early 1960s can hardly be accused of excessive optimism. The Control of the Arms Race in particular resembles a demolition job on the arguments for international disarmament and leaves little room for notions of unrelenting international progress. Schelling catches this atmosphere well, noting in his review that he agreed with John Strachey that the book ‘offers only wisdom and perspective rather than bright hopes’.^[75] It is noticeable that strategic studies academics, whose subject displaces economics as the true dismal science, seem drawn to the noticeably pessimistic refrain in Bull’s work of the 1960s which also infected good parts of The Anarchical Society.

But, as some scholars have observed, the so-called ‘later Bull’ seemed to allow more scope for what he called the ‘solidarist’ interpretation of international society where the interests of the whole international community would increasingly dominate the plural interests of individual states. This theme is evident in Bull’s early work. It is certainly there in The Anarchical Society: Alderson and Hurrell note that one of the readers of the manuscript described the work as ‘hopelessly over-optimistic’.^[76] By the early 1980s, some of Bull’s work may even risk echoing the Kantian arguments he rejected earlier on. For example, his arguments for the just treatment of ‘third world’ countries within the international system, and to ‘some degree of commitment to the cause of individual human rights on a world scale’^[77] seem some distance from the brilliant grumpiness of his earlier writings, partially infused as these were with the melancholy of power politics. This increasing cosmopolitan streak may help explain why Bull has been claimed by some scholars as an early constructivist.^[78] The appeal here is not just because this later work might be read to imply the primacy of evolving social norms over hard power, but also because the evolution of Bull’s own thinking might be read as an example of the social construction of ideas.

Of course, this also means that in Bull’s work in particular there is something for just about everyone. It is just possible that a baby bear, mama bear and papa bear would all find parts of his work to their liking, or at least tasty enough to require a response. The same is true for strategists, for members of the English School—both explicit and tacit, for positivist and post-positivist international relations scholars, and also for those who belong to more than one of these categories. This is why it is especially apt that so many of us will be inhabiting the Hedley Bull Centre.